Use CSS Flexbox for Canvas layouts

Canvas offers a robust platform for educators and students to engage in interactive learning experiences. With web technologies evolving, the integration of advanced layout techniques like CSS Flexbox has become increasingly relevant. This introductory guide explores how to use HTML and CSS for compelling layout designs using Flexbox. 

Canvas, designed with educational integrity and platform stability in mind, imposes certain restrictions on HTML and CSS usage. These limitations aim to protect users from security vulnerabilities and ensure a consistent experience. Understanding the scope of these restrictions is crucial for developers and instructional designers looking to customise their course layouts effectively. 

CSS Flexbox is a one-dimensional layout system that allows developers to create flexible and responsive designs with ease. It’s a built-in layout model natively supported by modern web browsers, which means it doesn’t rely on external CSS frameworks or libraries like Bootstrap. This native browser support makes Flexbox a powerful and efficient tool for creating layouts directly with CSS, without the need for additional stylesheets or dependencies. 

An important advantage when using Flexbox in Canvas is that the layout will display correctly in the Rich Content Editor (RCE). This means that as you’re editing your content in Canvas, you’ll see an accurate representation of how your Flexbox layout will appear to students, making it easier to design and refine your course materials. 

Unlike traditional layout methods, Flexbox offers precise control over the alignment, distribution, and order of elements within a container. Key concepts include: 

• Flex containers, which define the flex context 
• Flex items, the content within the flex container 
• Main axis and cross axis, which determine the layout direction 

By leveraging these built-in browser capabilities, developers can create sophisticated layouts with less code and greater flexibility compared to older CSS techniques or external frameworks. 

Despite Canvas’s limitations, CSS Flexbox can be creatively applied to enhance course layouts. By embedding custom CSS within Canvas’s allowed HTML elements, educators can implement flexible layouts that significantly improve content organisation and visual appeal. Let’s explore some examples and code snippets to illustrate how CSS Flexbox can be adapted to fit within Canvas’s framework, emphasising compatibility and responsiveness. 

Example 1: A flexible 3-column layout 

Let’s create a responsive three-column layout using CSS Flexbox, tailored for displaying content dynamically across various screen sizes. 

<div style="padding: 30px;"> 

  <div style="display: flex; flex-wrap: wrap; gap: 20px; padding: 10px;"> 

    <div style="flex: 1 1 250px; text-align: left;"> 
      <h3>Column 1</h3> 
      <p>Content for the first column goes here.</p> 
    </div> 

    <div style="flex: 1 1 250px; text-align: left;"> 
      <h3>Column 2</h3> 
      <p>Content for the second column goes here.</p> 
    </div> 

    <div style="flex: 1 1 250px; text-align: left;"> 
      <h3>Column 3</h3> 
      <p>Content for the third column goes here.</p> 
    </div> 

  </div> 
</div> 

Let’s break down how each part of this Flexbox layout works: 

• Outer <div> Container:  
  • padding: 30px;: Creates space around the entire flex container. 

• Flex Container:  
  • display: flex;: Establishes a flex context for its children. 
  • flex-wrap: wrap;: Allows flex items to wrap onto multiple lines as needed. 
  • gap: 20px;: Sets consistent spacing between flex items. 
  • padding: 10px;: Adds internal spacing within the flex container. 

• Flex Items (individual <div> elements):  
  • flex: 1 1 250px;: This shorthand property sets:  
    • flex-grow: 1: Allows items to grow and fill available space. 
    • flex-shrink: 1: Allows items to shrink if necessary. 
    • flex-basis: 250px;: Sets the initial main size of the item. 
  • text-align: left;: Aligns text to the left within each item. 

This layout is responsive and will adjust based on the viewport size. On larger screens, it displays all items in one row. As the screen size reduces, items will wrap to new lines, maintaining at least 250px width, ensuring the content remains accessible and visually appealing across all devices. 

Example 2: Flexbox Cards

Now, let’s create a responsive series of ‘cards’ using CSS Flexbox, designed to adapt to varying screen sizes while maintaining a visually appealing layout. 

<div style="display: flex; flex-wrap: wrap; gap: 20px; width: 100%;
justify-content: center;"> 

    <div style="padding: 10px; min-width: 250px; flex: 1 1 250px; 
max-width: 100%;"> 

        <div class="cont" style="border: 10px solid #ebebeb; 
width: 100%; border-radius: 30px;"> 

            <div class="image" style="display: flex; justify-content:
center; padding: 20px;"><img style="float: left;" role="presentation"
src="https://fakeimg.pl/380x222/" alt="" /></div> 

            <h3 style="padding: 15px 5px 0px 20px; text-align: left;
font-size: 1.25rem;"><a class="inline_disabled" href="#"
target="_blank" rel="noopener">Header Text</a></h3> 

            <p class="text" style="padding: 0px 10px 10px 10px;
margin: 0px 10px 10px 10px; font-size: 1rem;">Lorem ipsum dolor sit
amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut
labore et dolore magna aliqua. Ut enim ad minim<div style="display:
flex; flex-wrap: wrap; gap: 20px; width: 100%; justify-content:
center;"> 

    <div style="padding: 10px; min-width: 250px; flex: 1 1 250px; max
width: 100%;"> 

        <div class="cont" style="border: 10px solid #ebebeb; width:
100%; border-radius: 30px;"> 

            <div class="image" style="display: flex; justify-content:
center; padding: 20px;"><img style="float: left;" role="presentation"
src="https://fakeimg.pl/380x222/" alt="" /></div> 

            <h3 style="padding: 15px 5px 0px 20px; text-align: left;
font-size: 1.25rem;"><a class="inline_disabled" href="#"
target="_blank" rel="noopener">Header Text</a></h3> 

            <p class="text" style="padding: 0px 10px 10px 10px;
margin: 0px 10px 10px 10px; font-size: 1rem;">Lorem ipsum dolor sit
amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut
labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea commodo
consequat.&nbsp;</p> 

        </div> 
    </div> 

    <div style="padding: 10px; min-width: 250px; flex: 1 1 250px; max
width: 100%;"> 

        <div class="cont" style="border: 10px solid #ebebeb; width:
100%; border-radius: 30px;"> 

            <div class="image" style="display: flex; justify-content:
center; padding: 20px;"><img style="float: left;" role="presentation"
src="https://fakeimg.pl/380x222/" alt="" /></div> 

            <h3 style="padding: 15px 5px 0px 20px; text-align: left;
font-size: 1.25rem;"><a class="inline_disabled" href="#"
target="_blank" rel="noopener">Header Text</a></h3> 

            <p class="text" style="padding: 0px 10px 10px 10px;
margin: 0px 10px 10px 10px; font-size: 1rem;">Lorem ipsum dolor sit
amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut
labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea commodo
consequat.&nbsp;</p> 

        </div> 
    </div> 

    <div style="padding: 10px; min-width: 250px; flex: 1 1 250px; max
width: 100%;"> 

        <div class="cont" style="border: 10px solid #ebebeb; width:
100%; border-radius: 30px;"> 

            <div class="image" style="display: flex; justify-content:
center; padding: 20px;"><img style="float: left;" role="presentation"
src="https://fakeimg.pl/380x222/" alt="" /></div> 

            <h3 style="padding: 15px 5px 0px 20px; text-align: left;
font-size: 1.25rem;"><a class="inline_disabled" href="#"
target="_blank" rel="noopener">Header Text</a></h3> 

            <p class="text" style="padding: 0px 10px 10px 10px;
margin: 0px 10px 10px 10px; font-size: 1rem;">Lorem ipsum dolor sit
amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut
labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea commodo
consequat.&nbsp;</p> 

        </div> 
    </div> 
</div> 

Let’s examine how this updated Flexbox layout works: 

• Flex Container:  
  • display: flex;: Establishes the container as a flex layout. 
  • flex-wrap: wrap; :Allows cards to wrap to the next line when there’s not enough space. 
  • gap: 20px;: Sets consistent spacing between cards. 
  • width: 100%;: Ensures the container takes up full width of its parent. 
  • justify-content: center;: Centres the cards horizontally within the container. 

• Individual Card Containers:  
  • padding: 10px;: Adds some space around each card. 
  • min-width: 250px;: Sets a minimum width for each card, ensuring they don’t become too narrow. 
  • flex: 1 1 250px;: This shorthand sets:  
    • flex-grow: 1: Allows cards to grow and fill available space. 
    • flex-shrink: 1: Allows cards to shrink if necessary. 
    • flex-basis: 250px;: Sets the initial width of each card. 
  • max-width: 100%;: Ensures cards don’t exceed the width of their container on smaller screens. 

• Card Content:  
  • The inner <div> with class “cont” creates the card appearance:  
    • border: 10px solid #ebebeb;: Adds a light border around the card. 
    • width: 100%;: Ensures the card content fills the width of its container. 
    • border-radius: 30px;: Gives the card rounded corners. 

• Image Container:  
  • display: flex;: Uses Flexbox for centring the image. 
  • justify-content: center;: Centres the image horizontally. 
  • padding: 20px;: Adds space around the image. 

• Header and Text Content:  
  • The <h3> and <p> elements have specific padding, margin, and font-size settings to create a consistent layout within each card. 

This layout is responsive and will adjust based on the available space: 

• On larger screens, it will display multiple cards in a row, with each card growing to fill available space (due to flex-grow: 1). 
• As the screen size reduces, cards will wrap to new lines (due to flex-wrap: wrap), maintaining their minimum width of 250px. 
• The max-width: 100% on the card containers ensures that on very small screens, the cards will shrink to fit the screen width without overflowing. 

This design ensures that the content remains accessible and visually appealing across all devices, from mobile phones to large desktop screens. The use of Flexbox allows for this responsive behaviour without the need for media queries, making the layout both flexible and maintainable. 

Leveraging CSS Flexbox within Canvas opens up new possibilities for creating dynamic and engaging educational content. While challenges exist due to platform restrictions, the benefits of a well-structured, flexible layout are undeniable. For further exploration, here are some resources to deepen your understanding of CSS Flexbox and discover advanced techniques for customising Canvas courses: 

• MDN Web Docs: Basic Concepts of Flexbox 
• CSS-Tricks: A Complete Guide to Flexbox 
• Flexbox Froggy: A game for learning Flexbox 

By mastering these Flexbox techniques and understanding how to work within Canvas’s constraints, you can create more engaging, responsive, and visually appealing course layouts that enhance the learning experience for your students.